The Nature of Collapse
by Laurie Bunter
Summary: A strange accident in Hueco Mundo occurs, forcing Byakuya to deal with unresolved issues with a certain vice captain... much sooner than he anticipated. Also implied IchiRuki, implied IshiHime. Spoilers for HM arc. Warning for light sensuality.


_This story owns a small debt to "Wasurenai" by Empatheia, the fanfic that originally 'converted' me to this absurd pairing. _

_Further apologies are extended to Kubo Tite, the long-suffering creator of Bleach. Please trust me, Yachiru was not harmed in the writing of this fic. I cannot vouch for Byakuya.

* * *

_

**The Nature of Collapse **

By Laurie Bunter

* * *

_**How wonderful that we have met with a paradox. Now we have some hope of making progress.**__ – attributed to Niels Bohr_

* * *

_  
_

Kuchiki Byakuya always wondered if transformation occurred in one solitary moment. Did change happen in a single thunderbolt? Or was change merely part of a gradual transition that occurred over a lengthy stretch of time? Did change only happen in a time period so long that would be impossible for one soul to document it unless he devoted his life waiting for its culmination?

Would a metamorphosis even exist, he mused, if no one was there to witness it?

The thought was patently absurd; it was like all the _koans_ he read as a child. Yet the niggling doubt existed. When did a near immortal such as he experience a change of heart, a shift in perspective?

Byakuya asked himself this question in light of recent events that he could not completely comprehend.

He was conscious that he was not an imaginative man; still, sometimes he wondered about these things.

For instance, nobody could deny that the old Inoue Orihime transformed into a goddess during her last moments. Yet not everybody was there to witness this singular event.

Perhaps, years from now, even the new Kuchiki Orihime would be the first to acknowledge this. The eye-witness accounts would have become fodder for folktale by then: how her fingers seized the Hougyoku from Aizen's desperate grasp and how she actually shoved it in her chest to protect it from further use. It was in that moment when the girl had momentarily transformed into a woman who knew what she was doing and what she was fighting for.

In Byakuya's estimation, it was simply too bad for the girl that only seconds later, her beautiful face took on the look of one drowning in amniotic fluid. Inoue Orihime then collapsed onto herself, struggling with an unseen force.

There was a blinding flash of fluorescent light, the type of bright that makes a person see the image of their own retinas when they close their lids. Then the Hougyoku was gone in an anti-climactic puff of dark smoke.

What remained startled the senses of Shinigami and Espada alike.

Orihime was still there when the smoke settled – or rather, a much younger version of her remained. Orihime had unmade it so thoroughly that time had reversed on her, and all that was left for Rukia to swaddle was a naked, auburn-haired baby enveloped in a bloodied Arrancar outfit.

Byakuya didn't have the heart to refuse Rukia's request to adopt the wee thing. He wasn't heartless, especially after Unohana said it was near impossible to reverse the damage and return Orihime to her teenage self. It wasn't safe to return her to the living world, either.

Byakuya didn't mind having another female around the mansion – it was the least he could for the girl's self-sacrifice for them all, and he was in a unique position to provide for her. He just wished that his new adopted niece had unmade the Hougyoku sooner, before her little fairy hairpins got out of her control and bounced about Hueco Mundo like so many ricocheting bullets.

In the midst of the chaos, Orihime's goddess-like powers of rejection in the hands of a startled little baby wrecked havoc on all those it touched.

It had hit Tousen, cursing him with sight at the moment of his death as a zanpakutou impaled his heart. It had briefly descended over Ulquiorra, causing his fake eyeball to pop out as a real pupil grew back painfully in its socket. It had momentarily cuffed Ichigo's Hollow mask, crumbling it to ashes and leaving Ichigo vulnerable at the very moment he was about to thrust Zangetsu into Grimmjow's stomach for the last time.

It even had hovered about Shunshui long enough to render that captain absolutely sober for the first time in centuries.

In particular, Byakuya wished that the Shun Shun Rikka had dissipated all their energy before Yachiru accidentally brushed against one of them, as she clung unobserved from Zaraki's boulder-like shoulder, late for the ensuing melee.

What had happened to Yachiru was the most frightening thing Byakuya ever witnessed in his lifetime.

Instead of turning back the clock for Yachiru, it seemed to propel her forward in time. Perhaps the act of rejection unmade the perennial child and forced her to take her real spiritual form.

For in a mere flicker of an eyelash, Yachiru lost her familiar, child-like contour and burgeoned into this unknown grown woman, all calves, hips, and winsome smile.

It did not help that Yachiru's clothes did not undergo the same mind-boggling growth spurt. The poor thing was distracted in the middle of a battle, trying to tug her suddenly short uniform over her adult thighs in a desperate attempt at modesty.

As the force of the transformation wrenched her off Kenpachi's shoulder, Yachiru blinked. Steadily approaching her was Nnoitra on a warpath; he had just mortally wounded Kira and was about to change murderous intent to rape the moment he glanced at her partially exposed chest.

Good thing her new sensual shape was enough distraction for the pervert in question for Yachiru to unleash her deadly shikai.

She didn't finish Nnoitra off in one blow, but hell, she did finish him off.

Byakuya shuddered. One should never cross the woman. That Arrancar's body was left in so many ribbons one could weave a basket out of him.

As soon as the dust settled from that brief sortie, Kenpachi had the decency to shed his raggedy captain's coat for her without so much as a backwards glance as he engaged all his new opponents with vigor. Perhaps he had sensed what had happened in that moment of rejection. Kenpachi was more astute than he was normally given credit for.

Byakuya was there when it all happened; he could not deny the event. He was lying on his back with a large gaping hole in his chest when it all went down. He thought that it was the last thing he would witness on the attack of Hueco Mundo when he lost consciousness.

When he woke up to see Isane hovering over him and smiling, in the back of his mind Byakuya remembered Yachiru right before his collapse. Oddly enough, he was not concerned about his own injuries.

Byakuya doubted his own memory of that moment of metamorphosis.

This is what bothered him the most: in the back of his mind, he secretly wondered whether there had been any real change at all.

* * *

"You heard about what happen to Yachiru-chan?"

"Strange, isn't it?"

"There are too many things we do not know about Miss Inoue's power. I think it bodes ill for the Kuchiki family to adopt her."

"They are keeping up with their new tradition for taking in strays."

"Too bad Miss Inoue didn't hit Captain Hitsugaya at the same time, as well. He could use the extra inches."

"We already have one-white haired stud of a captain. We don't have space for another."

And so went the endless talk and speculation in Soul Society. For months after the final curtain call of Aizen and Co., no one could think or talk of anything else.

Byakuya was too wrapped up in his own concerns to notice the buzz. He had already faced his home invaded by Rukia's human friends who seemed intent on staying with them indefinitely until Orihime grew up. A Quincy was already paying homage to the little baby. Byakuya had to gently tell the young man that a marriage proposal at this time of her life was unacceptable. Ishida merely replied, "I just want you to know that the offer is on the table, and that it should be the first to be considered when she comes of age." There was melancholy in his voice.

There were a few things in life that Byakuya could control, and so he did. The first was that under no circumstances would Orihime's power continue to go unchecked. Unohana and her most capable officers spent hours chanting kidou incantations to temporarily bind and seal her fairies. It was not an easy task.

Byakuya said it was simply to keep the new nursery safe and safeguard his property but Rukia knew better. If she and Ichigo swallowed their smirks, Byakuya didn't notice it. In fact, he hardly paid attention to the Shinigami representative who seemed to have temporarily moved in for the time being.

The second thing that he did control was this: Byakuya made sure that Ichigo's bedroom was in the guest house, the farthest possible location from the main section of the mansion and Rukia's private quarters.

The hint was broad enough to be accepted at face value.

Too bad Byakuya couldn't control who had access to his office, his last refuge from the reign of confusion that currently existed in his household.

* * *

One day Byakuya came in yet another boring assessment meeting with Yamamoto when he found an unwanted visitor waiting for him.

Yachiru was sitting on his captain's table, her velvety black eyes twinkling. It looked like she had snuck in through the open window.

It would have been adorable if she still looked like a seven-year old. Unfortunately, the Shinigami sitting on his desk had tripled in age and doubled in size since she last perched on the same spot six months ago.

She looked vaguely provocative sitting there.

It did not help that the same seamstress who made Matsumoto and Nemu's uniforms was the one commissioned to make her new shihakushou. The grown Yachiru was not as bosomy as the 10th division vice-captain or as daringly leggy as the other fukataichou. Still, she was getting close to exposing more skin than Byakuya thought was necessary for a seated officer.

The only thing about her appearance that pleased him was the lack of wheels on her zanpakutou; it was a vast improvement. Still, it bothered him that she had brought it along on her visit.

Was she going to threaten him with that thing?

"Get off," Byakuya said with more firmness than usual. "You're not a child anymore."

She pouted, the curve of her lips showing her dislike of his usual tone. "You used to be much nicer to me, Bya-kun."

"Why are you here, Yachiru?" Byakuya asked curtly, as he walked around the desk to close the open window.

"For more of the usual," she shrugged. "Candy and a chance to bother my favorite person."

Byakuya opened the top drawer and revealed a secret stash of confetti candy and various boxes of chocolate.

He gestured wordlessly for her to pick an item.

"You were more fun when you used to shove things into my mouth," she said.

"That course of action is hardly appropriate now," he answered.

"No pork buns today?"

Byakuya was annoyed. "None."

Yachiru leaned over the desk and picked the sole box of dark chocolate. Byakuya's eyes marginally narrowed in surprise. She had repeatedly ignored the same box several times in the past; it might have been the oldest in the collection.

"You don't like dark chocolate."

She smiled back as she opened the package, revealing gold-foiled dark chocolate thins. "A funny thing about being transformed by rejection," she remarked, "Is that what was once dismissed as detestable is now deemed essential to one's existence."

Byakuya did not answer that.

She bit into her first chocolate, and then her second.

Yachiru worked her way through the box, eating more neatly than she did as a child, but Byakuya was still tempted to wipe a non-existent smudge off her nose just to prove a point.

It was not a good idea to touch her, he thought hastily. He left the room without a word to ask an underling to bring him some tea.

When he returned with a chastised unseated officer in tow, bearing a tea tray, Byakuya did not expect Yachiru to still be in possession of his office. Often she left him alone as soon as he fed her.

Yet she was still there, sitting on his desk littered with twisted gold foils. It was as if she had taken root on that spot and wasn't going to budge until she underwent yet another chrysalis.

The unseated officer cleaned off the unoccupied space of the desk of debris, set down the tea tray, and silently withdrew.

"Perhaps you would care to leave a busy captain to his tasks?" Byakuya said sharply, settling himself down in his chair. He moved it slightly to one side as to avoid grazing her knees. He was sure he didn't want the young woman to collapse from a sugar-induced high on his hardwood furniture. It was best to be his usual dismissive self and maybe she would finally get the hint. "I am not so fortunate as Kenpachi to have a hard-working fukataichou as yourself to help me with my paperwork."

Yachiru didn't miss a beat. "You don't have anything pending now," she said evenly. "I asked Renji before I visited. We have all the time in the world."

Byakuya was at a loss. Many times he regretted that his vice-captain had such a big, uncouth mouth.

He was about to lean forward to pour himself some jasmine tea when Yachiru helped herself to the porcelain pot.

"How rude not to supply your guest with her own cup," she chided him. "We will just have to share."

Without leave she blew softly on the scalding tea and drank it to the dregs. Yachiru re-filled the cup and handed it to him expectantly.

He blinked. He was losing this strange test of wills. She seemed to think he would refuse and go without his own refreshment, so he accepted it and placed his lips to the cup.

As Byakuya sipped, he realized what he savored was not just tea and the pleasure of fine porcelain against his lips, but also something more delicate and feminine. The rim of the cup tasted lightly of cherry lip-gloss.

Yachiru smothered a smile. Through a teacup, they had just shared their first open-mouth kiss.

Byakuya put down the cup abruptly.

Was this woman-child not going to leave him alone today?

"And how is your new niece?" she inquired.

"Colicky." Unwillingly, the shadow of a smile appeared on Byakuya's face. As much as he tried to hide it, he loved the idea of a baby in his home: especially a pretty one that occasionally cooed and prattled. "Rukia is having trouble with her at night. A new nurse was installed to help with Orihime's care but Rukia would insist on doing things her own way."

"And who does this amuse the most? Ichigo, Renji, or you?"

"It amuses us all." The words were out before he knew it.

Byakuya should not have responded to her banter. A lowering of defenses, especially in the art of conversation, revealed his weakness.

He decided to change tactics and pull rank.

"You should treat me and the office I hold with more respect," he admonished. "Please, get off my desk."

"Yes, get off your desk because you're the heir to the Kuchiki clan," Yachiru yawned. "While I'm the head of the Shinigami Women's Association, frequent guest of the first division monthly tea parties as hosted by Yama-ji himself, a regular member of Unohana's ikebana classes, and the fukataichou of the eleventh division, the most feared squadron of all. I'm the eyes and ears of Soul Society, Bya-kun. I know things Soifon's boys don't. So don't mess with me."

She had a point there. Byakuya was about to speak when she cut him off.

"Don't open your mouth, unless you want me to silence you with a kiss."

The threat was real even if it was laced with coyness. For some reason Byakuya almost missed the child Yachiru that messed with him because this woman in her stead was nerve-racking for reasons he could not comprehend.

Kuchiki Byakuya was often a very dense, stubborn man.

"Cat got your tongue?" Yachiru inquired. "Good. Have some confetti candy."

She popped open the drawer and shook out a packet. The pastel-coated almonds poured into her hand as she waited for him.

"Do you intend to feed me that junk?"

"You must eat some of it," she reasoned. "I can't be the only reason why you keep so much… unless there are other things you would like to admit to right now, instead of keeping your mouth full."

With no possible retort that couldn't be twisted into a sexual innuendo, Byakuya was infuriated with the chit.

Yachiru waited and moved slightly closer to his chair. Byakuya opened his mouth reluctantly and she popped in the candy with her fingertips lightly brushing against his lips.

Byakuya swallowed with difficulty. He forgot to chew. Yachiru watched his throat muscles with mild concern and then poured him another cup of lukewarm tea. He gulped it down.

"So what do you plan to do about me?" she asked.

"Your question is based on many assumptions," he answered. "I have no prior knowledge that anything is supposed to be 'done' with you, aside from physically removing you from my presence."

"You can hardly ignore the truth of the matter," Yachiru retorted. "You've been entertaining my attentions for several months now."

"You said so yourself, you visit everyone as it suits you," Byakuya said, non-committal.

"But you're the only one who feeds me personally," she said, smiling. "Tell me, Bya-kun, does Rukia-chan know where you keep your secret manga stash in that big library of yours? Does Renji know that you secretly confiscated his favorite pair of living world bell-bottoms, because it offended your sense of style?"

He glowered at her.

It was a glare fit to kill but Yachiru merely giggled. "Everyone thinks you're so difficult to read. Funny how I got you pinned down."

Byakuya suddenly grew tired of this conversation. "Then dish out your dirt and be gone," he snapped. "I don't care for cheap blackmail. What do you want from me – the rest of my carp? Don't think for a second I don't know it was you who stole them from my pond and released them at the lake of the 13th division."

Yachiru smiled again. "Oh but you have more than enough," she argued. "I was merely cheering up Ukitake."

"So… you have stopped calling him Coughing-chan?"

"I can hardly hope to get away with that nickname now," she cocked an elegant eyebrow. "Unless you think I can."

Byakuya didn't say what was on his mind._ Yachiru, you can get away with anything. _

Intuition told her, however, the spirit of his thought. Always one to grab the advantage when she could, today Yachiru took the offensive a bit farther than she originally planned.

She leaned over, breached the invisible wall between them and touched the top of his head.

Strange. A man with such sharp reflexes like Byakuya could have blocked her caress if it was truly unwanted.

He seemed to have stopped breathing.

Slowly, with more gentle dexterity than he even imagined, Yachiru removed his kenseikan. Her warm fingertips brushes against his scalp and left his head feeling curiously light-headed. She finger-combed through his free tresses, caressing each silken strand that flowed through her sensitive tips. "There," she said. "Isn't that better? You always looked so stressed out with that thing on your head."

Byakuya wished he knew what had brought on the sudden change in topic. Ukitake was a far way from him. But perhaps not to Yachiru, who treated everyone exactly as she saw fit and cut everyone down to her size.

Her face was so close to Byakuya that he could see the tiny freckles on her cheeks that burned a permanent blush on her china-doll complexion. As a child she had looked like a clown with those freckles and that candy cotton hair. Transformed into what was the proper shape of her soul, her hair had darkened to a soft shade of scarlet that curled around her ever-inquisitive eyes.

Byakuya never imagined she would grow up to be so beautiful.

Her smile was not seductive. He could not think of Yachiru in those terms. It was too soon. She still retained that playful aura of an innocent. She had the makings of a spirited flirt. Yes, that was it.

Yet as her fingers swept through his hair, brushing lightly against the sides of his neck and even down his nape, pushing away the interfering windflower scarf as if it was a nuisance, Byakuya felt himself unwinding to her touch. It was as if his body had accepted what was inevitable before his mind had given in.

The moment of collapse was inevitable. Fight against it as he much as he would, Byakuya knew he was doomed.

"You asked me what I wanted from you," she said. "There is nothing among your possessions that would satisfy my greedy curiosity. I only wish to know all your secrets; you have so many of them. I want nothing you cannot give freely of your own will."

"That is a high price to pay."

"There is nothing to bargain for here. Do you realize that you are the first to truly recognize I am not a child and that I never was one? I merely acted that way because it fit my physical appearance, and it was convenient for me to be underestimated."

"It's easy to forget that you lived so long in the 79th district on your own," he acknowledged hesitantly.

Yachiru nodded. "This won't be the first time you understood someone from Rukongai."

Byakuya didn't flinch at her reference to Hisana. "Yes. I understood her very well."

She continued to touch him and Byakuya felt himself slip into a rose-tinted reverie. When was the last time that someone had fondled him with so much tenderness?

"I want you to know, I will not die on you," she whispered. "I will not cling to you except when you want me to."

"And what do you think you are doing now?" he swallowed.

"Just making my statement of intent clear," she said, as her fingers suddenly left his shoulder and came to rest primly on her lap.

Byakuya felt bereft. Without thinking, he leaned forward and lunged for her hand. Then, not knowing what to do with it once he got it, Byakuya did the unthinkable. He unfurled her fingers and kissed each digit separately, passionately, letting his lips going over every inch of each delicate fingertip. Once he was done, he turned it over and traced over the lines and dips of her limb, from the base of her pinkie to the pulse at her wrist.

He then planted a chaste kiss at the very center of her open palm.

Byakuya did not want to look up and encounter her glance. It would make everything too real.

He closed his eyes.

Byakuya did not see Yachiru push herself off the table, her eyelashes lowered, her cheeks suddenly pale and drained of color. All he could hear was the soft landing of her feet on the tiled floor and the swish of her uniform as she moved.

He did not see anything. Instead, he felt everything.

Her hands – against so close to him – brushed against his face, this time lightly studying the contours of his forehead, the curves and furrows of his eyes, the smooth planes of his cheeks, the bridge of his nose, and ended with the tip of his chin. One hand came to rest softly on his shoulder; the other was pressed against his chest, her thumb rubbing against the slight hollow between his collarbones.

For her to do so meant that she was standing now, right in front of him, and if he wanted to – he deemed it possible – all he had to do was to grab her by the waist and she would land into his arms.

Was this what Yachiru had intended to do so all along? Byakuya let her decide on her own, if she wanted to tread the path where this was all truly heading. He had his pride and he needed to keep his hands to himself. He had done so for long it was like second nature to him not to lose control.

He _hated_ it when he lost all self-possession.

He already revealed more than he should have.

A soft rustling of cloth near his ear, the still-forbidden feel of her body next to his: Yachiru bent towards him, taking up more of his personal space.

Byakuya could feel her light breathing against his cheek. He felt himself being wound up in a cocoon of her reiatsu, her exuberant spirit enfolding and caressing him, making him her very own precious toy.

He could do the same to her. There were many things he could do that would only shock her. Yachiru was still an innocent, despite her new form. He had been deprived of so many pleasures; he would be glad to teach her. She had played the child too long, and he had played along with her. But now the blinders were off and the chase had truly begun.

Byakuya was not ready to touch her with anything beyond what was proper. Even if his scarlet spirit threads wanted to wrap around her wrists and bind him to her on this chair, he was not ready at this very moment. Perhaps, neither was she.

She seemed to know the thoughts that had crossed his mind.

Before he realized what he was doing – perhaps before he knew what sort of commitment it symbolized – Byakuya felt himself slowly pull off his windflower silk scarf by one end. He knew he would feel naked without it, but at this point it hardly mattered. Blindly, he tried to drape it over her head. He seemed to have made it fall over her shoulders.

He wondered how it would look on her if she were clothed in nothing else.

"I do not demand this token," she said.

"I merely offer," he answered.

An unexpected amount of tenderness crept into her gaze. "Thank you for the sweets," Yachiru said gently in his ear. "I'll come again when you're free."

When Byakuya finally had the courage to open his eyes, the window was ajar, and she was gone.

Byakuya knew that her curiosity was aroused. She would come back soon. Otherwise, it would be a devil of a job to hunt her down.

Yachiru was one woman whose speed matched his own. She may get easily sidetracked, but she always knew where she was heading.

This time around, she was hurtling towards him alone, and Byakuya was going to welcome the intrusion.

* * *

_Author's notes:_

_**Koans**__ are questions, stories or statements used in Zen Buddhism that used in meditation, prayer, or open the mind to other forms of thinking._

_Popular examples include "What is the sound of one-hand clapping?" and "If a tree falls in a forest with no one around, does it make a sound?"_

_December 19, 2007. There is a new sequel to this story entitled "Uncertainty Principle." Unfortunately, it's beyond a M rating. If you are of legal age in your country of origin, you may read it at MediaMiner or my author's homepage._

* * *

_  
_

_Reviews are highly appreciated. Thank you for reading! _


End file.
